2-phase stepper motor is the most common stepper motor and also the choice with best performance ratio. Therefore, under the circumstance of no special requirements, it is necessary to give priority in choosing the 2-phase stepper motor. The 2-pahse stepper motors are mainly hybrid stepper motors. The smoothness of 2-phase stepper is not better than that of 3-phase and 5-phase stepper motor. However, the usage requirements of majority of users can be satisfied under the circumstance of subdivided drive. The stepping angle of 2-pahse hybrid stepping angle is generally 1.8° and 0.9°, first of which is common while 0.9° will be taken into account for the occasion of low-velocity rotation. As for 2-pahse hybrid stepper motor, there are also stepping angles namely 3.6° and 3.75°, which are not common. The stepping angle with large stepping angle is applicable for the occasion of high-velocity rotation, featuring relatively low noise.The size range of common flange of 2-phase stepping motor is 20-110mm. Compared to the stepper motor with larger size of flange, 3-phase stepper motor is more advantageous. Meanwhile, compared to the stepper motor with smaller size of flange, PM stepper motor has obvious advantage over size and cost.